Pharmacodynamics & Pharmacokinetics

Question 1

What is pharmacodynamics?

Answer 1

Pharmacodynamics is the study of how drugs affect the body. Considering the biochemical, molecular and physiological effects.

Question 2

What is pharmacokinetics?

Answer 2

Pharmacokinetics explores the organisms effect on the drug. Exploring the journey of the substance throughout the body: absorption, distribution, metabolism, excretion.

Question 3

What are the 4 stages of pharmacokinetics?

Answer 3

The 4 stages of pharmacokinetics: ADME. Absorption, Distribution, Metabolism, Excretion.

Question 4

Describe ABSORPTION

Answer 4

ABSORPTION: How the drug moves from the administration site to distribution .

Question 5

Describe DISTRIBUTION

Answer 5

DISTRIBUTION: How the drug travels via the bloodstream to other tissues in the body.

Question 6

What does TDM stand for?

Answer 6

TDM stands for therapeutic drug monitoring

Question 7

Define EFFECT

Answer 7

EFFECT: The type of response produced by the drug

Question 8

Define ACTION

Answer 8

ACTION: how and where the effect is produced

Question 9

Give 3 examples of dietary related elements that have a pharmacological effect

Answer 9

3 EXAMPLES of dietary related elements with a pharmacological effect: Caffeine (for alertness), Glucose (for energy), Heavy meal (sedation)

Question 10

Give TWO examples of dietary elements that can interact with medicines

Answer 10

GRAPEFRUIT and ALCOHOL are dietary elements that can interact with medicines

Question 11

Define AFFINITY

Answer 11

AFFINITY: how tightly a substance binds to a receptor

Question 12

Define LIGAND

Answer 12

LIGAND: molecules that bind to a receptor

Question 13

If AFFINITY is HIGH, is MORE or LESS drug required?

Answer 13

If AFFINITY is HIGH, LESS drug is needed.

Question 14

If AFFINITY is LOW, is MORE or LESS drug required?

Answer 14

If AFFINITY is LOW, MORE drug is needed.

Question 15

What is there a risk of if more drugs are taken?

Answer 15

If more drugs are taken there is a greater risk of side effects and toxicity.

Question 16

Receptor

Answer 16

Receptor:
* Target molecule that a ligand binds to to produce a specific effect
* A unique recognition site for a specific ligand
* Macromolecule
* Most are proteins
* Found on cell surface, cytoplasm or nucleus

Question 17

Transduction

Answer 17

Transduction:
* A chain of events that produces a particular effect after a ligand binds to a recptor

Question 18

Non-receptor targets

Answer 18

Non-receptor targets:
* Targets for antacids and gaseous anaesthetics
* Targets for drugs that do not use receptors

Question 19

Intrinsic activity

Answer 19

Intrinsic activity:
* A measure of the agonists ability to generate an activating stimulus and produce a change in cellular activity
* The effect you can see/measure

Question 20

Potency

Answer 20

Potency:
* Concentration required for 50% of the maximal response to be expressed

Question 21

Occupancy theory

Answer 21

Occupancy theory:
* The more receptors occupied the greater the response
* Not always true

Question 22

Spare receptors

Answer 22

Spare receptors
* Maximum effect can be seen before all receptors are bound

Question 23

Threshold

Answer 23

Threshold
* Some ligands can bind to the receptor BEFORE producing a response

Question 24

The smaller the dissociation constant the _______ the binding

Answer 24

The smaller the dissociation constant the tighter the binding

Question 25

Volume of distribution

Answer 25

Volume of distribution:
* Tells us where the drug is
* Amount known
* Concentration known
Volume of distribution is the extent to which a drug is distributed throughout the body in relation to its concentration in the bloodstream. It is a useful measure as it can influence dosing considerations and can help to understand how a drug is distributed. If a drug possesses a high volume of distribution this infers that is more distributed to the tissues, whereas a drug that possesses a low volume of distribution will be found in the bloodstream.
* Calculate volume
* 5L in bloodstream
* 40L total body water
* 1300L elsewhere
* Plasma protein binding